<b 


*B    llfl    «m 


EXCHANGE 


BlOLOGi 
LIBRA** 


31 

The  Graphic  Recording 

of  Reflexes,  Clonus 

and  Tremors 

A  Thesis  Submitted  to  the  Faculty  of  the  Graduate  School 
of  the  University  of  Minnesota 

BY 

R.  EDWIN  MORRIS,  M.  D. 

IN  PARTIAL  FULFILLMENT  OF  THE  REQUIREMENTS  FOR  THE 
DEGREE  OF  DOCTOR  OF  SCI1 


1917 


[Reprinted  from  MINNESOTA  MEDICINE,  July,  1919] 


THE  H.  W.  KINGSTON  COMPANY 

527-533  Minnesota  Street 

St.  Paul,  Minn. 


*  -^Reprinted  from  MINNESOTA  MEDICINE,  July1 


THE  GRAPHIC  RECORDING  OF  REFLEXES, 
CLONUS  AND  TREMORS. 


R.  EDWIN  MORRIS,  M.  D. 

of  Medicine.  University 
Medical  School. 

Minneapolis,  Minn. 


Department  of  Medicine.  University  of  Minnesota 
Medical  School. 


In  undertaking  this  work,  two  great  prob- 
lems were  confronted — 1st.  The  securing  of 
consistant  constant  graphic  records  of  the  re- 
flexes, clonus  and  tremors ;  2nd.  Their  interpre- 
tation and  the  underlying  physiological  basis. 

So  many  were  the  difficulties  and  so  great 
the  time  consumed  in  attempting  to  solve  the 
first  problem  that  all  questions  of  interpreta- 
tion will  be  deferred  for  later  communication. 

Prominent  among  the  early  workers  making 
accurate  studies  and  contributions  to  our 
knowledge  of  nervous  phenomena,  is  Marshall 
Hall1,  whose  findings,  demonstrating  the  reflex 
or  excito-motor  system  of  nerves,  were  pub- 
lished in  1838.  Within  the  next  decade  he  dem- 
onstrated that  the  posterior  columns  of  the 
cord  were  sensory,  while  the  anterior  were 
motor  in  function. 

Preceding  and  leading  up  to  these  important 
discoveries  of  Hall,  were  several  investigations 
worthy  of  mention  in  this  connection.  J.  H. 
Miller2,  of  Baltimore,  started  his  work  in  1809 
and  demonstrated  important  functions  in  rela- 
tion to  the  great  sympathetic  plexus  of  nerves 
and  included  information  relating  to  this  work 
in  his  lecture  delivered  at  the  Washington 
Medical  College  in  1827.  Brachet3,  carrying  on 
researches  in  France,  also  made  important  con- 
tributions. Perhaps  most  important,  however, 


444250 


m  Ar£'.the:  brilliant  discoveries  of  Sir  Chas.  Bell  of 
London4  demonstrating  the  distinct  sensory  and 
motor  functions  of  the  posterior  and  anterior 
roots  of  the  spinal  cord.  His  publication  ap- 
peared in  1824.  An  earlier  communication  of 
Hall's  presented  to  the  Royal  Medical  Society 
of  England  in  1833  should  also  be  mentioned. 

Though  the  work  of  these  men  was  conducted 
independently,  they  arrived  at  the  same  general 
conclusions  and  established  definitely  that  the 
sympathetic  plexus  is  connected  with  the  pos- 
terior column  of  the  cord  and  that  the  motor 
impulses  pass  from  the  anterior  roots. 

Three  other  important  contributions  should 
be  mentioned  before  taking  up  the  work  of 
Westphal  and  Erb.  George  Morton5,  of  Phila- 
delphia, published  a  research  in  nerve  physi- 
ology in  1839,  entitled  "Grania  Americanae. " 
The  work  of  Magendie  Floures6  on  the  relation 
of  the  brain  and  medulla  oblongata  to  the  func- 
tions of  the  cord,  and  that  of  H.  H.  Smith,7  are 
to  be  mentioned  in  connection  with  the  develop- 
ment of  our  knowledge  of  the  various  reflexes. 

Since  Westphal  and  Erb8  recognized  the 
values  and  introduced  studies  on  the  knee  jerk, 
or  patellar  tendon  reflex,  it  has  been  a  fruitful 
field  for  scientific  research  and  extensive  litera- 
ture has  been  gathered  about  it.  The  work  of 
Puerbringer9  on  section  of  the  cord  in  the  upper 
dorsal  region  of  rabbits  showed  that  lively  knee 
jerks  could  be  elicited  despite  the  claim  of 
Rosenthal  and  Mendelsohn10  that,  after  trans- 
section  of  the  cord  at  different  levels,  the  knee 
jerk  is  lost,  and  that  the  production  of  the 
reflexes  required  an  intact  arc  in  the  region  of 
the  cervical  enlargement. 

In  the  work  of  Gad  and  Flatau11  with  high 
trans-section  of  the  cord  in  dogs,  weak  knee 
jerks  were  obtained  or  were  sometimes  tern- 


porarily  abolished,  though  with  low  trans-sec- 
tion of  the  cord  the  knee  jerk  continued. 

A  short  time  later  Sherrington12  conducted 
comprehensive  and  extended  studies  on  the 
knee  jerk  in  monkeys,  doing  trans-section  at 
various  levels,  and  also  observed  carefully  all 
the  other  reflexes  affected.  His  report  shows 
that  knee  jerks  were  lost  for  a  time,  though  in 
cats  and  dogs  that  were  transsected  at  the  same 
time,  the  reflexes  were  not  lost  even  on  trans- 
section  as  high  as  the  cervical  region.  The  re- 
sulting shock  produces  a  temporary  disturb- 
ance, which  in  man  is  of  longer  duration. 

Following  this  Margulies13  demonstrated  that 
cutting  the  cord  produced  lesions  resulting  in 
flaccid  palsy,  and  crushing  the  cord  produced 
lesions  resulting  in  loss  of  the  knee  jerks. 

Stewart  P.  Turner14  concludes  that,  though 
his  findings  were  not  constant  on  section  in 
other  animals,  in  monkeys  the  higher  the  level 
of  trans-section  the  greater  the  likelihood  of  loss 
of  the  knee  jerk,  while  in  man  transverse  injury 
above  the  lumbar  enlargement  usually  leads  to 
loss  of  the  knee  jerk,  though  in  complete  trans- 
verse injury  it  abolishes  it  only  temporarily. 
Trans-section  produces  an  impaired  neuro- 
muscular  tone.  Voluntary  movement  is  abol- 
ished while  the  true  reflex  is  not  impaired.  A 
great  autonomy  exists  in  the  spinal  segments 
in  maintaining  neuro-muscular  tone  as  we  de- 
scend the  vertebrate  scale. 

The  work  of  Buchanan15  done  with  frogs, 
particularly  in  electric  stimulation  and  the 
timing  of  reflexes,  to  my  mind  shows  only  that 
the  action  of  a  carefully  excised  frog's  muscle 
suspended  in  salt  solution  will  differ  greatly 
from  that  of  the  human  muscle  in  normal  or 
abnormal  conditions.  Waller16  did  important 
work  along  the  same  lines,  publishing  his  re- 

3 


suits  in  the  early  eighties.  Lombard's  work17 
on  the  normal  knee  jerk  is  one  of  the  most  mas- 
terly studies  made  up  to  that  time.  In  sum- 
ming up  his  conclusions,  he  says — "It  is  highly 
probable  that  the  tendon  phenomenon  is  a 
direct  muscular  contact  and  the  integrity  of  the 
nervous  arc  is  necessary  for  its  production." 

Neuro-pathologists  of  the  present  day  are 
following  the  teaching  of  Bastian  that  the  cord 
is  not  the  absolute  center  of  reflexes:  though 
there  appears  with  most  transverse  lesions  an 
increase  in  reflexes,  the  consensus  of  opinion  is 
now  that  the  tendon  reflexes  are  independent 
of  nervous  action  beyond  the  spinal  cord. 

Laborde  (quoted  by  Jendrassik)  reports  in- 
stances showing  that  tendon  reflexes  persist  af- 
ter decapitation:  hence  brain  action  is  not  re- 
quired for  the  production  of  all  reflexes. 
Sahli13  believes  that  the  cerebrum  is  essential. 
In  contrast  to  the  earlier  ideas,  Jendrassik19  has 
formulated  a  theory  of  reflexes  which  is  based 
upon  clinical  evidence  and  is  worth  care"ul 
consideration,  "Reflexes  are  spinal  or  cerebral 
or  a  combination  of  the  two."  Sahli,  discussing 
the  subdivisions  of  Jendrassik,  says  that  "they 
do  not  consistently  hold  good"  and  he  suggests 
that  Jendrassik 's  group  3  be  'called  cortico- 
nuclear,  and  those  involving  the  spinal  areas 
of  innervation  be  called  cerebrospinal  reflexes, 
because  in  a  transverse  lesion  of  the  cord  the 
cerebellar  reflex  arc  is  also  interrupted  and  one 
would  expect  a  loss  of  cutaneous  reflexes,  but 
this  does  not  occur  since  the  lesion  interrupts 
the  sensory  conduction  through  the  cord  and  in 
a  measure  dams  the  sensory  stimulation.  (Jend- 
rassik's  group  3).  To  this  group  belong  reflexes 
which  have  complicated  centers,  within  which 
the  reflex  occurs,  not  as  a  single  movement  but 
as  a  series  of  such,  e.  g.,  sneezing,  vomiting, 


swallowing,  coughing,  urinating,  defecating, 
genital  reflex  (ejaculation).  Therefore  the 
peripheral  impulse  must  find  a  path  in  the 
region  of  the  lower  cord  segment.  It  generally 
selects  the  customary  path  (the  formed  spinal 
reflex  arc)  of  the  coresponding  cerebrospinal 
reflex  and  so  the  cutaneous  reflexes  become 
purely  spinal.  This  explains  how  many  of  the 
preserved  reflexes  retain  their  complete  and 
identical  distribution.  It  also  explains  how 
other  reflexes,  by  means  of  the  damming  up  of 
the  exciting  impulses  at  the  lesion,  attain  both 
abnormal  intensity  and  distribution  by  trans- 
mission of  the  impulse  to  the  neighboring  paths. 

Sahli's  theory  contrasted  with  Jendrassik's 
simplifies  the  scheme  of  reflexes.  There  are 
two  groups  of  reflexes:  (1)  spinal,  or  better, 
nuclear,  because  some  of  them  occupy  the  re- 
gion of  the  cranial  nerves  and  would  include 
the  .tendon,  periosteal  and  joint  reflexes:  (2) 
the  cerebrospinal  or  cerebro-nuclear  reflexes, 
including  both  normal,  cutaneous  and  mucous 
membrane  reflexes  and  including  also  Jend- 
rassik's group  3.  In  the  latter  group  the  brain 
and  spinal  cord  act  normally  together:  that  is, 
the  activity  in  the  lower  nuclear  reflex  arc  is 
under  physiologic  conditions  discharged  by 
the  cortex.  In  transverse  lesions  of  the  cord, 
reflexes  of  the  second  group  may  originate  ex- 
clusively by  way  of  the  cord  and  so  be  in- 
creased or  even  deformed  by  reflex  damming. 

Lombard20  made  careful  studies  in  the  varia- 
tions of  the  knee  jerk.  Bowditch  and  "Warren21 
conducted  interesting  investigations  as  to  the 
time  element  in  the  knee  jerk  and  the  effect  of 
reinforcement.  Waller22,  in  a  very  instructive 
article,  reviews  the  work  of  Lombard23  and  of 
Bowditch  and  Warren  and  sums  up  in  conclu- 
sion as  follows:  "It  is  highly  probably, that  the 


tendon  phenomenon  is  a  direct  muscular  can- 
traction  and  the  integrity  of  the  nerve  arc  is 
necessary  for  its  production."  Devising  some 
new  apparatus,  he  secured  excellent  records  of 
the  knee  jerk  with  time  portrayal.  On  the  com- 
pletion of  his  experimental  work  with  rabbits 
he  concludes:  "The  so-called  tendon  reflex  is 
a  phenomenon  of  direct  excitation,  its  lost  time 
is  practically  identical  with  that  of  direct  con- 
traction, whereas  the  lost  time  of  a  reflex  con- 
traction is  three  times  as  long". 

Other  experimenters  have  shown  that  the  in- 
tegrity of  the  spinal  arc  is  a  necessary  condi- 
tion. This  time  consideration  as  indicated  by 
Waller,  is,  in  my  opinion,  the  most  effective 
argument  yet  brought  against  the  theory  of 
reflex  contraction. 

The  reflex  may  be  obtained  with  the  patient 
either  in  a  sitting  or  recumbent  position.  If 
the  patient  is  in  bed,  flex  the  knee  to  an  obtuse 
angle,  the  heel  resting  on  the  bed,  support  the 
knee  with  the  left  hand  and  tap  the  patellar 
tendon  with  the  hammer  and  if  the  contraction 
is  produced,  the  quadriceps  extensor — if  the 
reflex  is  active — may  cause  extension  of  the  leg : 
if  it  is  faint,  the  contraction  may  be  just  visible 
underneath  the  skin,  though  care  should  be 
taken  that  the  jar  of  tapping  the  tendons  does 
not  produce  a  movement  that  resembles  the 
reflex.  Be  sure  that  the  muscles  of  the  leg  are 
not  tense.  This  can  be  tested  by  suddenly  re- 
moving the  supporting  hand  and  if  the  muscles 
are  relaxed  the  leg  will  drop  to  the  bed.  This 
reflex  may  be  reinforced  according  to  the  meth- 
od of  Jendrassik,  pulling  on  the  two  hands 
hooked  together. 

If  the  reflex  is  elicited  with  the  patient  in 
sitting  posture  he  is  seated  with  legs  crossed  or 
with  feet  flat  upon  the  floor  and  legs  as  nearly 


vertical  as  possible.  A  better  method  is  to  have 
the  patient  seated  on  a  table  or  edge  of  a  bed, 
with  legs  hanging  free.  By  placing  the  left 
hand  on  the  thigh  above  the  knee  while  tapping 
with  the  right  hand,  a  contraction  will  be  felt 
with  the  left  hand.  On  tapping  the  left  fore- 
finger placed  over  the  patellar  tendon,  in- 
creased extension  of  the  tendon  may  be  felt. 

The  method  of  Lanfanauer's  reinforcement24 
may  be  used.  The  patient  is  seated  with  both 
feet  touching  the  floor,  the  examiner  grasps  the 
quadriceps  with  the  left  hand  and  the  patient 
grasps  the  upper  left  arm  of  the  examiner.  As 
the  patient  squeezes  the  arm  of  the  examiner 
the  tendon  is  tapped  with  the  hammer.  In 
Schonborn's  method25  of  reinforcement  the  pa- 
tient squeezes  the  left  hand  of  the  examiner 
while  the  latter  taps  the  tendon  with  the  ham- 
mer held  in  the  right  hand. 

Knee  jerks,  as  existing  in  apparently  normal 
individuals,  are  usually  described  as  absent, 
mild,  strong  and  exaggerated.  Very  extensive 
scales  describing  the  degree  of  this  phenomenon 
have  been  used,  as  many  as  ten  degrees  or  vari- 
ations being  described  in  thus  designating  the 
strength  of  the  reflex26. 

A  normal  reflex  is  evidence  that  the  spinal 
segment,  by  which  it  is  connected  with  the  ex- 
tremities of  the  arc,  Fig.  1.  is  in  a  state  of 
physical  harmony.  When  there  is  a  diminished 
reflex  or  an  absence  of  reflex  there  is  some  inter- 
ruption of  the  reflex  arc.  This  arc  leads  from  the 
peripheral  end  organs,  through  the  sensory 
nerves  leading  to  the  posterior  sensory  gan- 
glia on  to  the  posterior  horn  through  the  seg- 
ments, thence  to  the  anterior  motor  roots  in  the 
anterior  horn  and  on  to  the  muscle. 

There  are  two  great  groups  of  reflexes,  super- 
ficial and  deep.  There  is  a  superficial  reflex 


Fig.  1. — I1.  Indirect  (sensory)  Tract,  (Deep  Reflex.) 

12.  Indirect  (involuntary)  Motor  Tract. 

13.  Route  of  the  Normal  Reflex  with  Results 
of  Lesions. 

action  coming  from  the  end  organs  in  the  su- 
perficial tissue  or  at  the  surface  of  the  skin: 
and  there  is  a  deep  reflex  or  action  coming  from 
the  muscle,  bone  or  tendon.  The  superficial  re- 
flexes enter  through  the  posterior  root  ganglia, 
at  the  arc  directly  through  the  cord  and  leave 
at  the  same  level  by  way  of  their  anterior 
motor  roots.  The  deep  reflexes  enter  in  the 
same  manner  through  the  posterior  root  gan- 
glia. From  there  they  pass  in  part  to  the  sen- 
sory root  of  the  cord  where  they  enter  and  fol- 
low the  indirect  sensory  tract  of  the  cortex. 


(Fig;.  I1.)  Others  pass  through  the  posterior 
horns  to  the  anterior  horn  where  the  sensory 
impulse  is  translated  to  a  motor  response. 
(Fig;.  I3.)  Where  the  p-overnine:  fibres  from  the 
cortex  through  the  indirect  motor  tract  join  the 
reflex  arc,  the  governing  action  either  is  in- 
hibited or  accompanied  by  the  impulse  from  the 
cortical  area.  (Fig.  I2.)  From  the  anterior  horn 
cell  the  impulse  passes  along  the  motor  nerve 
to  the  muscle. 

Phelps27,  in  a  study  at  the  Minnesota  State 
Hospital  for  the  Insane  at  Rochester,  has  care- 
fully searched  the  literature  of  the  knee  jerk. 
He  says,  "Rather  surprisingly  there  is  no  scale 
by  which  to  measure  the  degree  of  this  phe- 
nomenon." In  his  work  he  finds  that  in  some 
persons  the  knee  jerk  was  quick  and  short:  in 
others,  longer  and  slower.  In  one  hundred 
normal  subjects  (attendants)  there  was  one 
case  of  absent  reflex.  This  case  was  observed 
over  a  year  and  also  two  normal  individuals 
showing  the  opposite  extreme — an  ankle  clonus. 
He  estimates  that  in  about  two  per  cent  of 
healthy  people  the  knee  jerk  is  absent,  though 
Jendrassik's  method  of  reinforcement  succeeds 
in  eliciting  it. 

Recently  a  strong  reaction  against  the  pre- 
valent conception  of  muscular  tonus  has  set 
in28.  It  is  maintained  that  there  is  no  such 
thing  as  a  general  contraction  of  muscle  when 
at  rest,  but  that  a  so-called  tonus  is  the  co- 
ordinative  performance  that  calls  forth  a  cer- 
tain attitude  by  means  of  finely  graduated  con- 
tractions. 

Many  of  the  so-called  pathologic  reflexes 
should  be  regarded  as  deformations  of  the  nor- 
mal reflexes  depending  upon  the  encroachment 
on  the  reflex  impulse  of  the  pathways  which  be- 
come accessible  to  the  impulse  only  because  of 

9 


an  obstruction  which  is  interposed  in  the  or- 
dinary reflex  tract  and  in  consequence  of  the 
reflex  damming.  The  reflex,  though  modified, 
can  still  be  recognized.  In  other  cases  reflexes 
occur  as  pathological  phenomena,  a  peculiar 
exageration  accompanied  by  reflex  movements 
of  a  distinctly  muscular  type. 

Sahli29,  in  closing  his  chapter  on  a  discussion 
of  the  segmental  localization  of  the  spinal  cord, 
says — '  *  The  frequent  contradictions  which  exist 
between  the  different  writers  show  how  unset- 
tled the  question  remains ;  that  accurate  clinical 
and  pathological  examinations  will  not  only 
supply  numerous  corrections  but  will  extend 
our  knowledge  as  well.  These  findings,  es- 
pecially where  they  concern  the  reflexes  and 
their  relation  to  the  segments,  must  be  critical- 
ly examined  for  light  on  the  genesis  of  re- 
flexes." 

Engaged  in  electrocardiographic  studies  dur- 
ing the  years  of  1914  and  1915  and  noting  in 
these  records  the  deflections  (extra-cardiac  or 
extraneous)  produced  by  voluntary  muscle 
movement,  the  writer  began  a  more  system- 
atic study  of  extraneous  voluntary  and  in- 
voluntary movements.  A  normal  muscular 
contraction  produced  a  definite  curve  or  series 
of  curves  while  muscular  contractions  asso- 
ciated with  some  pathological  conditions,  as 
tremors,  produced  a  definite  type  of  oscillations 
of  the  galvanometer  string.  These  oscilla- 
tions passed  through  stages  according  to  the 
degree  of  involvement,  to  a  definite  series  of 
rhythmic  oscillations  as  observed  in  clonus. 
Noting  the  constant  recurrence  of  these  rec- 
ords of  muscular  response,  serious  attempts 
were  made  to  secure  definite  records  of  con- 
traction of  different  groups  of  muscles.  Se- 

10 


curing  constant  results  from  these,  attempts 
were  made  to  secure  records  of  various  reflexes. 

The  results  were  so  promising  that  early  in 
the  spring  of  1916,  with  the  assistance  of  Dr. 
Henry  "W.  Woltmann,  a  systematic  study  of 
various  reflexes  and  tremors  was  begun  and 
graphic  records  were  made  with  the  string 
galvanometer,  using  the  same  instrument  as 
that  employed  for  studying  action  currents  in 
the  heart. 

Our  instrument  is  the  Cambridge  Modifica- 
tion of  the  Einthoven  String  Galvanometer,  or 
electrocardiograh.  (Fig.  2.) 

Our  earlier  records  were  secured  at  the  time 
of  making  the  regular  electrocardiographic 
runs,  at  the  electrocardiographic  station:  with 
the  recording  apparatus  in  Millard  Hall,  Uni- 
versity of  Minnesota:  the  sending  stations  on 
the  different  floors  of  the  University  Hospital: 
the  connection  through  under-ground  cables 
some  1390  feet  long.  Communication  with  the 
operator  was  had  by  telephone  wires  passing 
through  the  cable. 

In  the  fall  of  1916  we  returned  to  Millard 
Hall,  taking  records  with  the  patients  in  the 
same  room  with  the  recording  apparatus.  The 
records  obtained  are  identical  in  type  with 
those  from  the  hospital.  The  writer  has  made 
several  new  appliances,  among  them  a  device 
for  recording  the  mechanical  swing  of  the  leg 
simultaneously  and  on  the  same  moving  photo- 
graphic paper  with  the  record  of  the  electric  ac- 
tion of  the  string  galvaro  meter.  Electric  con- 
tact is  made  by  recording  the  exact  time  of  the 
blow,  giving  the  signal  on  the  margin  of  the 
paper. 

Our  attentions  has  been  centered  principally 
upon  the  study  of  the  knee  jerk  and  in  record- 
ing this  reflex.  The  i  ppar^tus  as  new  (m 

11 


Fig.  2. — Apparatus  in  use  at  Millard  Hall,  University 
of  Minnesota. 

ployed  consists  of  a  chair  (Fig.  3.)  (1)  with 
arms  and  back  in  order  that  the  patient  may 
sit  in  as  comfortable  a  position  as  possible. 
The  chair  is  elevated  sufficiently  so  that  the  feet 
swing  free  from  the  floor.  Attached  to  the 
front  edge  of  the  chair  are  two  light  boards 
(F)  that  are  fastened  to  the  back  of  the  pa- 
tient's leg.  The  upper  end  of  each  board  is  at- 
tached by  a  hinged  joint  to  a  rod  (T)  that  runs 
along  the  front  edge  of  the  chair,  permitting 
a  lateral  movement  in  order  to  adjust  the  leg 
boards  comfortably  to  the  legs  of  the  patient. 
A  vertical  rod  (E)  passes  through  the  centre  of 
the  front  edge  of  the  chair  passing  through  a 
collar  and  is  held  in  place  by  a  set  screw  (V) 
so  that  it  can  be  raised  or  lowered  in  adjusting 
the  hammer  position.  The  rod  bends  forward 
at  right  angles  at  the  upper  end  and  to  this  is 
attached  a  double  set  screw  (S)  which  holds 
in  position  a  rod  (M)  that  passes  at  right 
angles  to  the  forward  end  of  the  hammer  sup- 

12 


port  and  is  parallel  to  the  front  edge  of  the 
chair.  This  rod  supports  the  hammer  (C)  in 
position  so  that  with  proper  adjustment  it  will 
strike  the  knee  in  the  same  spot  each  time  and 
give  blows  of  the  same  intensity  as  many  times 
as  desired.  The  "electrical  release"  was  tried, 
but  catching  the  hammer  on  the  rebound  with 
the  hand  and  elevating  it  to  the  desired  po- 
sition, then  releasing,  permits  using  a  much 
simpler  apparatus. 

Several  types  of  hammers  have  been  used. 
Our  earlier  work  was  done  with  the  ordinary 
percussion  hammer,  the  blow  being  given  with 
the  hammer  held  in  the  hand  of  the  observer. 
Later  this  was  modified  in  order  to  record  elec- 
trically the  moment  of  the  blow.  A  little  later 
the  writer  devised  the  swinging  hammer  held  in 
position  by  the  support  described  above.  A 
small  metal-headed  hammer  was  used,  the  metal 
head  being  placed  in  electric  circuit,  a  small 
piece  of  metal  gauze  (D)  being  placed  over  the 
patellar  tendon  and  being  insulated  so  that  no 
portion  of  it  touched  the  body.  This  was  placed 
in  the  circuit  with  a  signal  magnet  placed  at 
the  lower  or  right  edge  of  the  slit  of  the  re- 
cording apparatus  of  the  electrocardiograph. 
Thus  at  the  moment  the  hammer  touched  the 
knee  the  circuit  was  closed  and  a  record  made 
of  the  moment  of  contact.  The  loss  of  time 
that  occurs  by  the  use  of  this  method  amounts 
to  approximately  one  fourtieth  of  a  second. 
The  hammer  handle  has  five  holes  in  it  which 
permit  it  being  hung  upon  the  adjustable  rod 
in  such  a  manner  as  to  allow  adjustment  for  a 
blow  of  greater  or  lesser  force. 

The  necessity  of  exact  control  in  the  strength 
of  the  blow  early  became  apparent.  This  was 
accomplished  in  two  ways.  1st.  by  varying  the 
length  of  the  arc  through  which  the  hammer 

13 


Fig.  '3. — The  chair  and  its  attachments,  used  in  Ob'ain- 
Reflexes.  Also  apparatus  (below)  in  obtaining 
Clcnus  Record. 

fell,  by  suspending  the  hammer  through  differ- 
ent holes  in  the  handle,  2nd,  by  allowing  it  to 
fall  either  45  or  90  degrees.  Figure  5a  shows 
effect  of  dropping  the  hammer  alternately 
through  45  and  90  degrees,  and  figure  5b,  the 
same  with  re-enforcement. 

The  later  model  of  hammer  has  a  double  con- 
tact head  that  does  away  with  attachment  of 
the  metal  gauze  connections  with  the  leg  so 

14 


that,  when  the  blow  is  struck,  a  cap  over  the 
head  of  the  hammer,  but  not  in  contact  with  it, 
is  forced  into  contact,  closes  the  circuit  and 
produces  the  swing  of  the  signal  magnet  indi- 
cating the  moment  of  the  blow.  The  apparatus 
is  arranged  so  that  both  legs  are  attached,  dou- 
ble swing  boards  and  electrodes  being  used. 
This  permits  the  securing  of  repeated  records 
of  the  same  leg  or  of  the  opposite  leg  under  the 
same  conditions  without  disturbing  the  subject. 

The  electrocardiograph,  such  as  we  use  in 
securing  our  cardiac  records,  consists  of  three 
units — a  lamp,  recording  apparatus,  and  an 
Einthoven  string  galvanometer. 

In  securing  records  of  knee  jerks,  the  subject 
is  seated  in  the  chair  described  above,  attach- 
ments are  made  to  the  galvanometer  by  means  of 
electroces  (K  and  L)  similar  to  those  used  in 
our  electrocardiographic  work,  one  electrode 
being  placed  upon  the  knee  (L)  and  one  placed 
on  the  chair  (K)  so  that  it  comes  in  contact 
with  the  sacral  region.  The  wires  leading  from 
either  electrode  pass  directly  to  the  string  gal- 
vanometer though  it  is  possible  to  carry  them 
to  any  distance.* 

The  attachment  to  the  string  galvanometer 
are  connected  to  Lead  I  and  Lead  II  of  the 
switch  board  and  if  a  third  record  is  desired, 
with  attachment  not  only  from  the  knee  to  the 
sacrum  but  to  the  spine,  there  is  attached  the 
Lead  III  which  permits  securing  further 
records  without  disturbing  the  subject  by  sim- 
ply throwing  a  switch  as  in  cardiographing. 

Various  time  markers  have  been  used,  giving 
records  of  one-tenth  to  one-hundreth  of  a  sec- 
ond. The  one-tenth  second  marker  is  the  one 
usually  employed  by  us  and  is  of  the  Harvey  type. 

*At  present  we  are  taking  records  in  the  same  room 
with  the  apparatus  and  also  from  the  University  Hos- 
pital, a  distance  of  about  1,500  feet. 

15 


Fig.    5. — Shows  effect  of  dropping  the  hammer  alter- 
nately through  45  and  90  degrees. 

The  apparatus  for  securing  the  mechanical 
swing  consists  of  the  swing  board  (F)  in  the 
inner  edge  of  which  are  inserted  three  eye- 
lets (0),  to  one  of  which  is  attached  a  hook 
which  is  secured  to  an  inelastic  cord  which  runs 
over  an  adjustable  frictionless  pulley  (H)  to  a 
hanging  indicator  suspended  in  front  of  the 
aperture  in  front  of  the  lens  of  the  electro- 
cardiograph. The  indicator  produces  a  shadow 
parallel  to  that  of  the  string  galvanometer. 
Holding  the  indicator  in  position  on  the  other 
side  is  a  coiled  ^e1  •  rringr  (B  in  P  Fia;.  2), 
the  tension  of  which  is  adjustable.  So  long  as 
the  indicator  remains  in  a  vertical  position  the 
tension  on  the  string  leading  to  the  swing  board 
is  constant.  This  apparatus  has  given  very  con- 
stant and  satisfactory  results  and  produces  a 
record  that  is  of  the  highest  value. 

The  record,  as  it  appears,  from  a  comparative 
point  of  view  at  the  extreme  left  or  upper  side 
of  the  paper  as  ordinarily  held,  indicates  the 
movement  of  the  time  marker :  next  comes  the 
record  of  the  galvanometer  string:  and  then 
the  record  of  the  mechanical  indicator :  and  at 
the  extreme  right  or  lower  side  of  the  record  is 
the  record  of  the  time  indicator. 

One  great  difficulty  that  presented  itself  in 
securing  records  of  reflexes  was  the  adjustment 

16 


of  the  string  of  the  galvanometer  so  that 
records  of  a  constant  value  could  be  secured. 
To  overcome  this  the  following  method  was 
used.  When  ready  to  secure  a  record,  the  sub- 
ject being  properly  attached  and  the  photo- 
graphic record  paper  started,  one  millivolt  of 
current  was  thrown  into  the  circuit  from  the 
switch  board,  the  string  of  the  galvanometer 
having  been  adjusted  previously  so  that  as 
nearly  as  possible  to  secure  a  deflection  of  10 
mm.  The  introduction  of  this  millivolt  of  cur- 
rent thus  produces  a  deviation  of  the  string  so 
that  the  width  of  this  primary  deflection  repre- 
sents 1  millivolt  (Fig.  4.  )Thus  we  have  a 
means  of  comparing  the  different  records. 

As  a  routine  practice  in  recording  knee  jerks, 
we  make  three  records  of  each  limb,  starting 
with  the  left :  first  the  knee  jerk,  then  the  knee 
jerk  doubly  reinforced,  and  then  a  voluntary 
swing  representing  as  nearly  as  possible  the 
swing  produced  by  the  reflex.  The  greater  care 
has  to  be  used  in  securing  the  normal  reflex  to 
have  the  patient  in  as  easy  and  comfortable  a 
position  as  possible,  with  the  eyes  closed  and 
the  thoughts  diverted  from  the  reflex  problem. 
Early  in  our  work  we  found  that  the  patient, 
being  on  the  qui  vive,  and  the  operator  of  the 
galvanometer  saying  "Now"  when  ready,  pro- 
duced a  reinforcement  or  increase  of  the  reflex. 
Since  then  the  operator  signals  by  raising  the 
hand  when  ready.  In  securing  the  reinforced 
knee  jerk,  a  double  reinforcement  is  used.  The 
subject  watches  the  hammer  drop  and,  the  mo- 
ment it  is  released,  pulls  quickly.  This  rein- 
forcement in  most  cases  produces  a  marked  in- 
crease in  the  electrical  reflex  Fig.  6  though 
in  some  subjects  it  has  more  of  an  inhibitory 
effect  on  the  mechanical,  the  subject  holding 
the  muscles  tense. 

17 


There  is  a  marked  increase  in  sluggish  re- 
flexes when  reinforced  by  Jendrassik's  method. 
In  Fig.  7  this  is  well  shown.  While  on  the  other 
hand  reinforcement  may  have  a  tendency  to 
decrease  secondary  and  tertiary  swings.  This 
is  well  shown  n  Fig.  to,  in  which  rec  1  and 
3  without  reinforcement  should  be  compared 
with  2  and  4  with  reinforcement.  In  our  ear- 
lier work,  the  records  taken  were  "f  s",  full 
swing,  "s  r"  swing  and  return,  that  is  the  leg 
was  stopped  after  completing  one  outward 
swing  and  return  to  stop.  These  records  do  not 
show  the  secondary  and  tertiary  swings.  As  in 
Fig.  *  hoi  h  tN  re  was  o  ten  a  jar  o  re- 
bound that  was  shown.  Later  records  con- 
sisted of  (a)  the  direct  blow,  (b)  the  blow  re- 
inforced, (c)  the  voluntary  swing,  resembling 
nearly  as  possible  the ;  movement  caused  by  the 
reflex  swing  of  the  leg,  with  as  complete  relaxa- 
tion as  possible.  The  patient,  having  been  in- 
structed as  to  the  voluntary  swing,  on  signal 
kicks  as  nearly  as  possible  in  the  same  swing 
as  produced  by  the  reflex. 

Three  records  are  usually  taken  of  each 
different  phase  for  comparison.  It  is  in- 
teresting to  note  in  certain  so-called  normal 
cases  that  there  may  be  a  marked  increase  or 
diminution  of  the  reflex  evidenced  with  suc- 
ceeding blows. 

In'  securing  a  record  of  the  knee  jerk,  the 
patient  is  seated  comfortably  in  the  chair  with 
sufficient  clothing  removed  to  easily  get  at  the 
parts  desired.  The  electrodes  are  placed  in 
position  with  the  same  care  as  in  cardiograph- 
ing,  being  covered  with  a  warm  felt  pad  satura- 
ted with  salt  solution  and  this  in  turn  covered 
with  a  piece  of  tissue  paper.  With  the  finger 
as  a  hammer,  the  point  of  greatest  reflex  action 
is  located  and  this  marked  with  a  pencil. 

18 


The  leg  swings  are  then  secured  to  the  leg  and 
the  cord  to  the  mechanical  indicator  is  attached 
and  adjusted.  The  hammer  is  then  placed  in 
position  and  adjusted  so  that  the  point  of  great- 
est blow  comes  directly  upon  the  spot  pre- 
viously marked.  If  a  stronger  blow  is  desired 
the  hammer  is  moved  to  one  of  the  holes  higher 
in  the  handle.  The  indicator  wire  can  be  placed 
in  position  so  that  a  blow  of  either  90°  or  45° 
can  be  determined.  This  means  that  a  blow  of 
half  or  full  strength  can  be  determined  without 
rearranging  the  apparatus.  Fig.  5. 

The  difference  of  the  knee  jerk  as  observed 
by  the  eye  and  as  recorded  by  our  graphic 
methods  is  indeed  marked.  The  knee  jerk  as 
ordinarily  elicited  may  appear  to  be  very  simi- 
lar, but  by  the  graphic  methods  of  recording 
may  be  extremely  different.  Cases,  that  by  the 
ordinary  method  show  no  knee  jerk,  may,  by 
the  graphic  method,  show  a  marked  electrical 
reaction  with  the  str  ny  g  Ivsnomet^t.  F  sj.  7 
The  initial  reflex  action  is  evidenced  by  the 
rapid  oscillation  of  the  string  resembling  the 
sharp  pointed  R-wave  of  the  cardiogram.  This 
is  usually  of  the  diphasic  type  as  the  R-S  wave, 
Fig.  63,  though  in  occasional  records,  as  in  neu- 
ritis, it  may  even  appear  as  quadriphasic.  This 
wave  which  we  deem  the  true  reflex  action  oc- 
curs in  a  very  small  fraction  of  a  second  after 
the  blow  is  struck  on  the  patellar  tendon.  Fol- 
lowing this  wave  comes  a  wave  or  series  of 
waves  that  are  identical  with  the  waves  secured 
in  the  voluntary  swing  of  the  leg  of  equal 
length.  Various  factors,  such  as  fatigue,  drugs 
and  toxic  conditions  in  general,  seem  to  influ- 
ence the  width  of  excursion  of  this  reflex  ac- 
tion, but  the  individual  type  of  record  remains 
constant  and  its  relation  to  the  inception  of  the 
oscillation  due  to  the  mechanical  swing  of  the 
leg  is  the  same. 

19 


Fig.  6. — Tracings  1  and  3  show  left  and  right  K.  K. 
Tracings  2  and  4  show  same  reinforced. 

Certain  cases  show  a  positive  initial  deflec- 
tion indicated  by  movement  toward  the  upper 
right  side  of  the  records  and  is  usually  of  op- 
posite polarity  to  the  reflex  itself. 

The  reflex  is  of  very  short  duration,  about 
one-fortieth  of  a  second.  At  present  we  have 
not  the  means  at  hand  to  accurately  measure 
this,  though  later  we  hope  to  make  a  study  of 
the  various  time  elements.  The  mechanical 
swing  of  the  leg  usually  begins  one-tenth  of  a 
second  after  the  reflex  action  and  may  consist 
of  a  single  swing,  or  as  many  as  five.  The  time 
element  varies  greatly  in  the  swing  in  return- 
ing to  the  base  line.  If  the  subject  holds  the 
leg  tense  it  is  evidenced  by  a  slower  ascent  and 
gradually  receding  descent  of  the  marker  to 
the  base  line,  Fig.  4.  This  has  been  termed, 
by  older  writers,  the  " inhibitory  effect."30 

The  knee  jerk  varies  in  different  individuals 
under  different  normal  conditions.  Though 
they  are  constant  under  similar  circumstances, 
they  may  be  greater  early  in  the  morning  than 
later  in  the  day  (fatigue) :  increased  after 

20 


meals:  increased  by  mental  activity:  increased 
by  cold,  voluntary  movements,  strong  sensory 
sensation,  or  emotion.  They  are  lost  in  sleep31. 

In  the  work  of  Lombard,32  Bowditch,33  War- 
ren34 and  Noyes35  elaborate  examinations  were 
made  of  this  feature  of  the  knee  jerk  and  exten- 
sive records  were  made  from  a  subject  by  use  of 
a  delicately  constructed  apparatus. 

Diller36  examined  the  knee  jerk  of  103  stu- 
dents whom  he  considered  normal.  In  no  case 
was  the  phenomenon  absent,  though  in  one-fifth 
of  the  cases  it  was  difficult  to  elicit,  and  re- 
peated blows  were  necessary  to  bring  it  out. 
His  conclusions  were  that  the  knee  jerk  varied 
greatly  in  length  and  rapidity  of  excursion.  He 
says,  "It  would  be  desirable  to  measure  defin- 
itely and  record  both  of  these  elements ". 

Mitchell  and  Lewis37,  in  summing  up  an  ex- 
tended research  of  the  knee  jerk,  say — "In 
some  the  same  weight  of  blow  causes  pretty 
constant  effect  when  steadily  repeated  at  like 
intervals,  but  in  others  the  effects  are  incon- 
stant and  a  series  of  slight  motions  are  apt  to  be 
followed  by  an  excessively  exaggerated  act. 
Such  persons  make  bad  subjects  for  experi- 
mentation. This  explosiveness  is  also  apt  to 
follow  much  excitation  of  the  muscle.  Even  in 
the  young  and  healthy  the  knee  jerk  varies 
markedly.  It  is  more  marked  in  the  morning, 
in  relaxing  states  of  the  weather,  disability, 
exhaustion,  all  tending  to  lessen  the  ease  of  the 
reply  to  the  tap. ' ' 

The  fatigue  of  a  reflex  is  sometimes  responsi- 
ble for  mistakes  in  diagnosis38.  The  response 
to  the  first  tap  should  be  observed  attentively 
because  it  may  disappear  after  one  or  two  repe- 
titions. In  testing  periosteal  and  tendon  re- 
flexes it  is  especially  important  to  use  great 
care  in  eliciting  reflexes,  and  to  distract  the  at- 

21 


Fig.  7. — Reinforcement  of  Sluggish  Reflexes.  On  left 
are  group  with  small  action.  On  right, 
same  under  reinforcement. 

tention  of  the  patient  from  the  part  to  be  ex- 
amined, for  through  voluntary  tension  the  re- 
flex may  be  inhibited. 

Individuals  show  a  constancy  in  type  of  re- 
flex that  has  continued  through  the  period  of 
our  observations.  The  quickness  with  which 
the  knee  jerk  responds  and  the  muscular  swing 
following  are  always  of  the  same  general  type 
though  they  may  be  modified  by  various  fac- 
tors. 

Knee  jerks  elicited  early  in  the  morning  are 
much  greater  than  those  secured  from  the  same 
individual  later  in  the  day  or  following  exten- 
sive physical  exercise.  Fatigue  exercises  a  re- 
markable influence  on  the  strength  and  quick- 
ness of  the  reflex.  I  have  taken  records  of 
runners  under  normal  conditions  and  immedi- 
ately following  long  cross-country  runs.  These 
records  show  decided  lessening  in  all  their 
forms.  I  have  taken  records,  using  the  same  in- 
dividual, and  secured  records  of  repeated 
blows.  Certain  individuals  show  no  marked 
change,  though  innumerable  taps  may  be  given, 
while  others  may  show  an  increasing  reflex  and 

22 


others  a  diminishing  reflex  with  succeeding 
taps. 

S.  Weir  Mitchell39  says  of  Jendrassik's  rein- 
forcement that,  "The  discovery  as  to  the  power 
of  the  voluntary  volitional  muscular  movement 
acts  to  increase  the  amount  of  the  knee  jerk". 
His  conclusions  are — "The  knee  jerk  is  a  true 
reflex  caused  by  mechanical  irritation  of  the 
nerves  of  the  tendon.  Duly  repeated  excita- 
tion of  the  knee  jerk  in  some  healthy  persons 
increase  the  knee  jerk.  Some  cases  show  grad- 
ual loss  to  oft  repeated  taps  and  the  muscle 
ceases  to  contract.  Such  movements  as  frown- 
ing, moving  the  scalp  or  ears,  moving  the  eyes, 
all  act  as  reinforcements.  Inspiration  and  ex- 
piration act  as  a  decided  reinforcement.  Sneez- 
ing, laughing,  acts  of  phonation,  swallowing, 
and  all  of  the  coarser  muscular  acts  increase 
the  knee  jerk.  Pain,  intense  fear  and  cold 
also  increase  it.'* 

Lombard40,  studying  the  knee  jerk  variations, 
demonstrated  that  fatigue,  hunger,  enervating 
weather  and  sleep  were  conditions  which  in- 
creased the  activity  of  the  whole  nervous  sys- 
tem, and,  in  consequence,  the  activity  of  the 
knee  jerks. 

It  is  a  constant  observation  that  the  re- 
flex action  of  the  right  leg  is  more  marked  than 
the  left,  as  is  also  the  accompanying  muscular 
reaction.  This  is  still  more  increased  by  rein- 
forcement. Inflammatory  conditions  of  muscle 
and  nerve  bring  out  a  marked  reflex  in- 
crease together  with  an  increased  muscular 
response,  though  here  the  action  is  more  irreg- 
ular due  to  the  irritation  present.  Former 
injuries  and  cases  giving  a  history  of  neuritis 
show  marked  decrease  even  to  absence  of  the 
knee  jerk  on  the  affected  side.  At  all  times 
great  care  must  be  used  in  securing  the  knee 

23 


03   OJ 
,Q    0> 

I 


II 


Fig.  8. — Knee  Kick  in  Case  of  Multiple  Sclerosis, 
a)  Time  marker,  b)  Electrical  response. 
c)  Mechanical  response. 

jerk,  for,  should  the  first  response  to  the  tap 
be  small,  the  examiner  might  consider  the  knee 
jerk  absent.  He  must  observe  each  reflex 
quickly  and  accurately  and  make  careful  re- 
peated examinations  in  order  to  determine 
definitely  their  presence  or  absence. 

Sahli41  says — "Any  psychic  excitement  con- 
siderably increases  the  tendon  reflexes  and  this 
increase  may  serve  as  an  important  sign  of  the 
states  of  psychic  excitement.  The  diminution 
of  reflex  sometimes  observed  in  very  acute,  espe- 
cially in  traumatic,  cord  lesions  is  acceptable  to 
the  theory  that  this  diminution  is  due  to  inhibi- 
tion or  to  injury  to  the  lower  cord  segments 
fr.om  circulatory  disturbances  from  the  injury. " 

An  injury  to  the  cord  produces  a  definite  type 
of  symptoms.  The  amount  of  trauma  can  only 
be  determined  by  time,  for  a  slight  injury  may 
show  an  absence  of  knee  jerk  for  a  few  days 
followed  by  complete  restoration  of  this  reflex. 
In  the  more  severe  lesions  a  trauma  may  show 
complete  loss  of  the  knee  jerk  with  no  return, 
due  to  shock.  These  produce  disturbances  of 
the  circulations  which  clear  up  within  a  few 
days.  Any  inflammatory  condition  of  the 
nerves  of  the  leg  will  cause  an  increase  of  the 

25 


Fig. '  9. — Tracings  1  and  3  show  sluggish  reflexes,    2  and 
4  same,  45  minutes  after  gr.  1-10  strychnia. 

knee  jerk.  Sciatica,  for  example,  produces  a 
marked  increase  of  the  affected  side  that  grad- 
ually becomes  normal  as  the  inflammatory  con- 
ditions recede.  A  hemiplegia,  due  to  hemor- 
rhage, produces  a  broken  arc  in  the  upper  arc, 
thus  cutting  off  the  inhibition  factor  and  caus- 
ing a  greater  knee  jerk  on  the  opposite  side 
from  the  lesion. 

As  has  been  mentioned  before,  a  few  appar- 
ently normal  cases  show  absence  of  the  knee 
jerk  (Westphal's  sign)42  by  the  ordinary  clin- 
ical method  of  eliciting  it,  yet,  with  our  method 
of  graphically  recording  reflexes,  a  minute  elec- 
tric reflex  action  Fig.  91,  followed  by  an  elec- 
tro-muscular action  is  recorded. 

Pathological  conditions  such  as  fatigue43, 
anesthesia  narcosis,  tabes44,  Fig.  10.  Entire 
absence  of  any  leg  swing  is  known  in  this  con- 
dition. This  failure  is  not  mechanical.  A  large 
number  of  the  tabetics  have  failed  to  show  any 

26 


effects  whatever ^of  electrical  change  when  the 
attempt  is  made  to  elicit  the  knee  kick.  Fig  10. 
Three  tracings  taken  at  three  different  times, 
over  a  period  of  two  months.  On  the  left  the 
reflex  record  and  on  the  right  the  voluntary 
swing.  Diabetes,  paraplegia,  poliomyelitis,  and 
in  acute  infections  for  a  short 'time,  also  the 
effects  of  certain  drugs  as  opiates,  may  cause 
a  diminution  of  the  reflex  action  from  a  clinical 
standpoint,  though,  by  our  graphic  method  of 
recording,  these  cases  will  show  a  small  reflex 
with  a  small  electro-muscular  and  mechanical 
response.  In  students  we  made  a  careful  study 
of  the  reflexes  as  effected  by  various  drugs, 
among  which  were  recorded,  prior  to  and  .one- 
half  hour  subsequent  to  the  administration  of 
caff  em,  grs.  5,  and  of  strychnia  sulphate,  one- 
tenth  gr,  An  increase  following  caffein  and  an 
increase  following  strychnia,  and  with  in- 
creasing response,  each  succeeding  blow.  The 
caffein  relieving  apparent  muscular  irrita- 
tion, while  the  strychnia  increases  the  irrita- 
bility. In  transverse  lesions  of  the  cord45,  the 
cutting  off  of  inhibition  from  the  centers  above 
markedly  increases  the  reflexes.  As  a  rule  the 
knee  jerk  is  permanently  absent  after  total 
transverse  lesions  of  the  spinal  cord  above  the 
level  of  the  arc  (Bastian's  law),  but  the  reason 
is  not  known. 

Certain  pathological  cases  present  an  in- 
crease of  both  reflexes  and  muscular  action, 
such  as  myelitis,  spastic  paraplegia,  multiple 
sclerosis60.  (Fig.  8)  and  lesions  that  cause  a 
degeneration  of  the  cord  itself.  Any  irritable 
condition  of  the  muscle,  as  in  some  of  the  toxic 
states  whether  from  stimulant  drugs  as  strych- 
nia, (Fig.  9)  or  internal  conditions,  increase 
the  knee  jerk. 

27 


Fig.  10. — Tracings  from  Tabetic,  over  period  3  months. 

Many  times  we  secure  records  of  knee  jerks 
that  present  peculiar  formation  in  type,  a  char- 
acteristic form  both  in  reflex  and  muscular  re- 
sponse, apparently  due  to  the  predominant 
action  of  certain  groups  of  muscle  bundles  in  a 
definite  manner.  These  individual  types  per- 
sist so  that  repeatedly  we  have  obtained  similar 
peculiar  records  from  the  same  subject. 

CLONUS. 

Clonus  may  be  defined  as  a  reflex  irregular 
contraction  of  muscles.  In  any  muscle  in  an 
irritable  stage  with  increased  tonus,  the  ten- 
dency to  clonus  action  is  greater  as  the  tone 
increases.  The  principal  clonus  described  by 
clinicians  are  the  ankle  clonus,  the  patellar 
clonus  and  the  jaw  clonus.  In  securing  ankle 
clonus,  the  knee  is  slightly  flexed,  the  heel  rest- 
ing on  the  palm  of  the  examiner 's  left  hand  and 
his  right  hand  grasping  the  foot,  extending  it 
and  suddenly  dorsi-flexing  the  foot  upon  the 
leg.  An  initial  series  of  clonic  involuntary  con- 
tractions of  the  muscles  of  the  calf  is  elicited 
and  repeated  under  sustained  pressure  of  the 
flexing  hand.  This  constitutes  true  clonus.  The 
patellar  clonus  is  elicited,  while  the  knee  is 
flexed  and  the  heel  resting  in  the  examiner's 
hand  as  before,  by  making  quick  and  sudden 

28 


pressure  with  the  thumb  and  forefinger  and 
suddenly  pushing  patella  downward  and  holding 
it  firmly.  A  clonus  of  the  quadriceps  extensor  is 
thus  produced.  The  jaw  clonus  is  produced  in 
a  similar  manner  by  suddenly  throwing  press- 
ure upon  the  masseter  muscles. 

True  clonus  has  the  same  significance  as  ex- 
aggerated knee  jerk,  and  its  relation  to  organic 
disease  is  most  common  in  disseminated  and 
lateral  sclerosis.  "If  contractions  appear  be- 
fore the  degree  of  foot  flexion  exceeds  a  right 
angle  and  are  evidently  voluntary,  irregular 
and  fleeting,  then  one  is  dealing  with  spurious 
clonus,  usually  hysterical"46.  Clonic  convul- 
sions are  rapid  involuntary  muscular  move- 
ments repeated  in  shocks  or  series  of  shocks 
with  force  and  rapidity.  They  are  never  oc- 
casioned by  peripheral  excitation  of  the  motor 
nerves.  There  appears  to  be  an  accumulative 
irritability  centre  whose  action  may  be  com- 
pared to  that  of  the  Leyden  jar,  and  seems  to 
be  essential  to  set  off  the  shock-like  explosions. 
Clonic  contractions  are  practically  always  ac- 
centuated either  by  direct  or  reflex  irritation  of 
the  motor  centre  whether  it  be  the  nuclear  or 
psycho-motor  centre  of  the  cortex.  Tonic  con- 
vulsions, long  continued,  produce  rapid  con- 
traction of  the  muscle  which  may  suddenly 
change  by  implication  and  position  or  tension 
of  muscle.  It  may  be  associated  with  or  trans- 
formed to  the  clonic  variety.  A  joint  firmly 
fixed  by  the  muscle  contracted  about  it  so  that  its 
movements  are  difficult  or  impossible  is  a  con- 
dition called  a  contracture.  The  increased  ten- 
sion of  the  muscle  may  depend  on  increased 
tonus.  The  active  contraction  is  an  irritative 
reflex  contraction  while  the  passive  contraction 
is  a  nutritive  shortening  of  muscle.  Active 
contractures  may  occur  where  muscle  tone  is 

29 


Fig.  12. — Records  of  Tremors,  normal  type. 

increased  since  muscular  tone  is  of  reflex 
origin. 

Bodwitch  and  Warren47,  in  an  article,  say — 
"  There  is  good  evidence  that  clonus  is  a 
mechanical  act  the  same  as  the  knee  jerk,  hence 
should  be  similarly  influenced  by  the  peripheral 
nerve  stimulation.  Clonus  may  be  reinforced  or 
inhibited  the  same  as  a  normal  knee  jerk  of  a 
healthy  individual." 

Ankle  clonus  presents  a  definite  record  by 
the  graphic  method  that  will  materially  assist 
in  a  better  understanding  of  the  work.  To  the 
unaided  eye  all  clonus  appears  alike,  but  rec- 
ords show  that  there  are  three  distinct  types80 
due  to  fundamental  genesis  underlying  as 
in  a  case  of  chronic  lenticular  degeneration, 
hematomyelia  and  primary  sclerosis.  A  con- 
stant record  may  be  obtained  not  only  showing 
the  rate  and  frequency  of  the  clonus  but  also 
its  strength  as  recorded  by  the  width  of  oscil- 
lations and  also  the  duration,  whether  main- 
tained for  some  time  or  quickly  dropping  off, 
and  the  question  of  its  fatigue  is  recorded  in  a 
permanent  and  definite  manner  Fig.  15. 

The  apparatus  used  in  securing  records  of 
clonus  is  shown  in  Fig.  3.  The  arm  band 
(Ss.)  and  pump  of  a  blood  pressure  apparatus  is 
fastened  about  the  limb  from  which  the  record 
is  desired.  Tubing  leads  to  the  Marey  tambour 

30 


(R)  which  replaces  the  recording  apparatus 
used  in  securing  the  mechanical  swing  of  the 
knee  jerk.  Slight  inflation  is  made  with  the 
pump.  The  electrodes  are  used  as  in  securing 
the  knee  jerk  and  are  attached  to  the  string 
galvanometer. 

TREMORS. 

Among  the  earlier  medical  writers  was  Clau- 
dius Galen48  who  noted  the  fact  that  tremor 
existed  and  differed  during  voluntary  move- 
ment and  repose.  Later  Vieussens,  in  the  latter 
part  of  the  14th  century,  was  the  first  to  point 
out  the  distinct  and  separate  parts  of  the  brain, 
and  wrote  extensively  on  the  subject  of  tremors. 

Haller49,  in  1708,  in  researches  on  irritability, 
established  the  existence  of  irritability  as  a 
property  of  living  muscular  tissue  and  that  sen- 
sibility was  due  to  the  nerves  alone. 

Gilson50,  the  successor  of  Harvey,  in  the  mid- 
dle of  the  17th  century  brought  out  many  new 
discoveries  regarding  nerve  tissue.  The  doc- 
trine of  irritability,  as  taught  by  Haller,  lead 
to  a  greater  physiological  study  of  nervous 
tissue. 

James  Parkinson51,  of  London,  in  1817  pub- 
lished his  essay  on  shaking  palsy  and  this  is  his 
greatest  and  most  important  contribution  to 
Medicine.  Parkinson's  definition  is — "Involun- 
tary tremations,  motion  with  lessened  muscular 
power  in  parts  not  in  action  even  when 
supported. '  * 

Tremors  are  rapid,  minute  muscular  contrac- 
tions with  a  rhythmic  tendency.  Tremor  may 
appear  in  healthy  individuals  as  well  as  in 
pathological  states,  hence  the  need  of  careful 
study  and  record.  It  may  appear  in  normal 
individuals  following  physical  exercises,  mental 
agitation,  cold,  etc.  Tremors  are  of  two  classes : 

31 


Fig.  15. — Record  of  Ankle  Clonus, 
(a)  intention,  or  that  occurring  during  pur- 
poseful movement,  and  (b)  passive,  or  that 
tremor  persisting  during  rest.  Putting  the  in- 
dividual muscle  group  in  action  or  under  con- 
tinued strain  increases  tremor.  All  tremors  of 
the  extremities  are  increased  by  extension  and 
may  be  wholly  absent  when  the  patient  is  at 
rest.  Most  tremors  are  a  spastic  phenomenon 
and  the  centres  are  located  above  the  reflex  arc. 
Sahli52  believed  that  tremors  are  essentially 
manifestations  of  spasm  just  as  every  spasm  is 
explained  by  the  damming  up  of  stimuli  which 
causes  an  explosive  instead  of  a  constant  dis- 
charge of  stimuli  from  the  ganglion  cells.  It  is 
analogous  to  the  spark  discharge  of  an  induc- 
tion apparatus  in  contrast  to  the  spray-like 
brush  discharge  following  low  resistance.  To 
continue  the  analogy  to  explosive  discharges 
further,  we  see  that  the  succession  of  impulses 
underlying  tremors  may  be  based  on  the 
stronger  stimulation  of  the  motor  ganglion  cells 
on  the  one  hand  through  the  central  neuron 
(paralysis  agitans  and  nerve  excitability),  or 
through  the  reflex  pathways  (multiple  scler- 
osis) on  the  other,  because  of  the  interruption 
of  the  motor  current  (peripheral  palsies,  fa- 
tigue, etc.)  In  all  these  cases  there  is  the  same 
disparity  between  the  afferent  and  efferent 
nerve  stimuli.  This  exposition  is  no  mere  hy- 

32 


pothesis.  It  rests  upon  the  well-known  general 
recognized  property  of  the  ganglion  cells  to 
accumulate  impulses  and  discharge  them  ex- 
plosively though  we  have  as  yet  no  further  ex- 
planation. It  suggests  a  fundamental  charac- 
teristic of  nerve  power  which  is  a  physiological 
observation.  This  brings  us  to  a  closer  under- 
standing of  the  different  types  of  physiological 
tremor. 

As  has  been  stated  previously,  as  a  result  of  a 
careful  study  of  the  various  irregularities  that 
appeared  upon  our  cardiograph  records  and 
finding  that  many  of  these  finer  movements 
were  due  to  tremors,  a  more  careful  study  of 
tremors  was  commenced,  and  soon  the  necessity 
was  apparent  of  an  apparatus  that  would 
graphically  record  the  various  movements  of 
tremors.  It  was  desired  that  this  apparatus 
should  be  small  and  compact  and  capable  of 
being  used  by  the  physician  in  general  practice. 
Fig.  13.  As  a  result  of  experiments,  the  'writer 
presented  the  Tremograph,60  Fig.  1  (L.  S.), 
and  demonstrated  its  use  at  the  Minnesota 
State  Medical  Society  in  the  fall  of  1916.  This 
apparatus  is  used  in  conjunction  with  the  re- 
cording apparatus  of  the  modified  McKenzie 
Polygraph  (B)53,  and  gives  a  light,  compact  ap- 
paratus for  making  definite  accurate  records 
of  tremors  and  clonus  in  a  permanent  form  and 
with  the  time  element  portrayed,  Fig.  14 

The  Tremograph  consists  of  two  tambours 
(E)  set  at  right  angles,  so  placed  that  one  is 
vertical  and  the  other  horizontal  to  the  axis 
of  movement.  These  tambours  are  connected 
with  the  tambours  of  the  modified  McKenzie 
polygraph  by  rubber  tubing.  (G).  The  move- 
ment to  be  recorded  is  accentuated  by  the  plac- 
ing of  spring  vibrators  of  steel  wire  (H)  in 
front  of  the  tambours.  Metal  olives  (F)  with 

33 


Fig.  13. — Tremograph. 

screw  adjustment  to  permit  their  being  placed 
in  different  positions  along  the  spring  vibrators, 
increase  the  oscillations  and  give  a  marked 
record  of  the  vibration.  Various  handles  are 
used  which  permit  the  securing  of  different 
types  of  records.  These  can  be  screwed  on  to 
the  apparatus  and  are  used  for  securing 
records  of  different  parts  of  the  body.  (A). 
Plain  round  handle  (C)  ordinarily  used  and 
held  in  either  hand.  (B).  The  tonometer  (D) 
with  screw  socket  placed  on  one  end  which  per- 
mits the  apparatus  being  used  for  securing 
pressure  tremors.  (C).  The  slightly  curved 
plate  2"x3"  with  two  straps  and  buckles  that 
permit  placing  it  immovably  on  any  part.  This 
is  especially  used  for  tremors  and  used  princi- 
pally on  the  lower  extremities. 

In  order  to  secure  analogous  records  of  pa- 
tients under  similar  conditions,  the  following 
procedure  is  adopted.  The  patient  is  made  as 
comfortable  as  possible,  whether  seated  erect 
in  a  chair  or  in  bed.  If  in  a  chair,  the  feet 
should  be  flat  on  the  floor  and  the  hands  on  the 
knees.  The  handle  of  the  Tremograph  is  then 
placed  in  one  of  the  patient's  hands  and  held 
between  the  thumb  and  extended  forefingers, 
the  horizontal  arm  to  the  front.  The  patient  is 
then  instructed  as  to  the  motion  to  be  made 
with  the  instrument.  The  following  move- 
ments have  been  used  by  us  in  securing  records 

34 


as"  being  representative  of  all  voluntary  move- 
ments. 

1.  "R.T."  (Rand  L)  "Best  Tremor ".    This 
record  is  secured  by  having  the  patient  raise 
the  hand  from  the  position  on  the  knee,   (a) 
front  and  upward  to  full  extension  of  arm,  (b) 
then  holding  arm  at  full  extension,  (c)  then  re- 
turning to  knee  position.    These  movements  are 
made  in  a  definite  time — five  seconds  to  each 
move  or  position,  the  rate  of  movement  being 
indicated  to  the  patient  by  the  operator's  arm. 
This  is  of  advantage,  as  the  attention  of  the  pa- 
tient is  focused  and  any  uneasiness  relieved. 

2.  "P.  T."    (R  and  L).    Pressure  Tremor, 
same  as  Rest  Tremor  only  tonometer  is  used  as 
handle  and  held  gently,  arm  raised  (1)  then  at 
full  extension,  (2)  the  patient  compresses  han- 
dle to  limit,  then  at  (3)  releases  to  gentle  grip 
and  return  to  knee.    Record  is  made  on  slip  of 
the  grip  pressure. 

3.  "F.N.T."  (R  and  L)  Finger  Nose  Test. 
The  round  handle  (A)  as  used  in  (1)  the  move- 
ment consists  of  four  positions,  each  occupying 
five  seconds — as  in  (1),  (a)  knee  to  full  exten- 
sion, (b)  then  elbow  is  bent  bringing  the  instru- 
ment, still  vertical  position,  close  to  nose,  then 
(c)    back  to  full  extension  and    (d)    back  to 
knee. 

4.  "R.  T.  Leg."  (R  and  L).    The  metal  pad 
(C)  used  and  attached  to  top  of  foot.     Each 
foot  is  brought  up   (a)   to  full  extension,   (b) 
held,  then  (c)  returned  to  floor. 

5.  "F.  K.  T.  of  Leg."  (R  and  L).  Foot  Knee 
Test.     (C)  attachment  as  in  (4)  movement  (a) 
to  full  extension,  (b)  foot  brought  close  to  oppo- 
site knee,  (c)  back  to  extension  and  (d)  back 
to  floor. 

This    produces    a    series    of   tracings   which 
cover  practically  all  the  common  movements. 

35 


Fig.  14. — Records  of  Tremors: 

a.  Exophthalmic  Goitre. 

b.  Exophthalmic  Goitre. 

c.  Chronic  Lenticular  Degeneration. 

d.  Multiple  Sclerosis. 

Tremors  of  the  tongue  may  be  tested  by  a 
little  aluminum  clip  attached  to  one  of  the 
spring  vibrators,  and  the  tremograph  attached 
to  some  solid  object.  The  tongue  is  placed  on 
the  aluminum  clip.  For  coarse  tremors  a 
smaller  sized  metal  olive  is  used  which  produces 
a  narrow  oscillation  of  the  writing  lever. 

In  eliciting  tremors  by  the  older  methods54 
"to  distinguish  between  passive  tremor 
and  intention  tremor,  direct  the  patient  to 
make  some  movement  such  as  taking  up  and 
fastening  a  collar  button,  buttoning  a  vest,  or 
drinking  a  glass  of  water.  In  this  latter  variety 
the  tremor  is  greatly  increased  by  the  co-ordi- 
nate movement  involved  and  indeed  may  be 
wholly  absent  when  the  patient  is  at  rest.  By 
resting  the  tips  of  the  patient's  fingers  (Quin- 
quad's  phenomenon)  upon  the  palm  of  the 
hand,  a  vibration  otherwise  imperceptible  may 
be  readily  detected."  This  is  the  usual  form  of 
noting  tremors  by  clinical  methods.  Though 

36 


this  does  not  give  a  definite  estimation  of  the 
rapidity  or  the  strength  of  the  tremor,  still 
with  a  careful  observation  by  this  method  the 
clinician  was  able  to  determine  whether  the 
tremor  was  fine  or  coarse. 

Many  types  of  apparatus  have  been  used  to 
estimate  and  record  graphically  the  various 
forms  of  tremor  but  all  of  them  were  cumber- 
some and  complicated  for  common  use. 

Warner55,  in  the  early  eighties,  brought  out 
interesting  but  complicated  apparatus  consist- 
ing of  an  arrangement  of  rubber  tubes,  one  for 
each  finger,  and  each  leading  by  the  piece  of 
tubing  to  an  elaborate  apparatus  with  a  smoked 
drum,  the  frame  supplied  with  recording  tam- 
bours and  electric  signals.  By  means  of  this 
apparatus  he  brought  out  some  interesting  fig- 
ures on  the  movements  of  the  hand  and  its 
various  parts. 

Various  other  devices  were  used  and  much 
valuable  data  has  been  gathered  by56  Grashey, 
Schafer,  Peterson,  Horsley,  Wolfenden,  Ewald, 
Gowers  and  Dana.  Peterson57,  in  1894,  pub- 
lished very  interesting  results  of  exhaustive 
work  on  tremors.  From  these  records  A.  E. 
Hennely  of  the  Edison  laboratory  constructed 
a  very  interesting  geometrical  chart  of  the  re- 
corded waves.  In  his  summary  Peterson  says 
— "  Compared  with  the  kymograph,  the  sphyg- 
mograph  is  coarse,  crude  and  uncertain  in  the 
reproduction  of  various  tremors.  Most  tremors 
can  be  placed  in  two  categories — fine,  from  10 
to  12  per  second:  and  coarse,  from  7  to  8  per 
second,  corresponding  to  the  normal  innerva- 
tion  rhythm  as  determined  by  Horsley  and 
Schaefer58.  A  slight  tremor  with  normal  in- 
nervation  wavelets  which  are  fused  in  groups 
of  two  gives  the  rate  of  5  per  second." 

37 


In  a  study  of  tremors  by  Neustaedter59  in 
1909,  he  brought  out  a  new  type  of  apparatus. 
By  means  of  this  apparatus  a  careful  study  of 
various  types  of  tremors  was  made  in  some  600 
cases  of  pathological  type.  His  conclusions  are 
as  follows :  "1.  I  want  to  say  that  the  difference 
between  different  tremors  are  of  kind,  not  of  de- 
gree, and  each  form  of  tremor  is  distinctive  of  a 
form  or  group  of  diseases."  2.  No  definite  re- 
lation exists  between  one  form  of  tremor  and 
any  other.  3.  The  frequency  of  movements 
has  no  bearing  upon  the  character  of  the 
tracing.  4.  There  is  no  material  difference  be- 
tween the  movements  of  the  two  sides  of  the 
body." 

CONCLUSIONS. 

1.  Graphic   records   of  reflexes,   clonus   and 
tremors  may  be  secured 

a.  By  means  of  the  string  galvanometer, 

b.  By  means  of  apparatus  recording  move- 
ments of  the  regions  involved,  i.  e.,  mechanical 
action.    Such  records  may  be  designated  broad- 
ly as  reflexograms. 

2.  Graphic  records  of  reflexes  may  be  secured 
showing  the  form  of  electrical  and  mechanical 
response  and  also  time  elapsing  between — 

a.  Stimulus  and  electrical  response  in  muscle. 

b.  Stimulus    and    mechanical    response    of 
parts. 

c.  Electrical  and  mechanical  responses. 

3.  In  the  normal  reflexogram  two  elements 
are  found : 

a.  An  initial  deflection  of  short  duration — 
probably  a  definite  reflex  response.  This  ap- 
pears to  be  present  only  in  the  records  of  elec- 
trical response. 

38 


b.  Definite  responses  due  to  muscular  action. 
These  show  both  in  the  records  of  electrical  and 
mechanical  response.  These  responses  may  be 
reinforced,  e.  g.,  by  Jendrassik's  method,  or  in- 
hibited, e.  g.,  by  psychic  factors,  producing 
probably  a  state  of  tension  or  resistance  in  the 
muscles  involved. 

4.  Tonus  plays  an  important  part  in  the  re- 
flex act.     Modifications  may  be  due  to  an  ab- 
normal    state     in    the     afferent    or     efferent 
segments  of  the  reflex  arc  and  to  conditions 
above  the  reflex  arc. 

5.  In  the  reflexograms  from  abnormal  indi- 
viduals, the  records  may  show  modification  of 
the  reflex  response   (diminution,  exaggeration 
or  perversion)  due  to  altered  conditions  from  fa- 
tigue, drugs  and  pathological  conditions  in  the 
reflex  arc  and  in  the  upper  neurons. 

6.  These  records  are  so  consistent,  definite 
and  permanent  as  to  have  a  medico-legal  value. 

7.  Irritability  may  be  increased,  in  varying 
degrees  and  when  this  is  sufficient,  clonus  may 
be  produced.     Clonus  records  show  rate,  am- 
plitude, duration,  response  to  increase  of  pres- 
sure by  the  manipulator,  and  fatigue. 

8.  Records  of  tremors  show  rate,  rhythm  and 
amplitude.    Tremor  occurs  in  normal  individu- 
als  and   in   them   is   increased   by   voluntary 
movement.    Tremor  is  modified  in  individuals, 
otherwise   normal,   by   such   factors   as   toxic 
states,  fatigue  and  drugs.     In  abnormal  indi- 
viduals alterations  in  rate,  rhythm,  amplitude 
and   effects    of   voluntary   movement    are   re- 
corded. 


39 


BIBLIOGRAPHY. 

1.  Hail,  Marshal.    History  of  Med.,  Davis,  '03. 

2.  Miller,  J.  H.  (1809).     Ibid. 

3.  Brachet,  Ibid. 

4.  Bell,  Sir  Chas.     (London).    Ibid. 

5.  Morton,  George  (Phil.  '39).    "Grama  Americanae." 

6.  Magnedie  Floures  (Barker). 

7.  Smith.  H.  H.,  (Barker). 

S.Westphal  and  Erb.,  Arch.  f.  Spychiartrie,  Vol.  V, 
1875,  p.  792.  Berl.  Klin.  Wochen.,  '81,  Vol.  18. 
Ibid.,  '78. 

9.  Fiirbringer,  Centralblat.  f.  med.  Wissenschr.,  1875, 
p.  929. 

10.  Rosenthal  and  Mendelsohn,— Monatschr.  d.  Roiiiel 

Akadem.  su.  Berl.  Feb.  '73.  Konigl.  Preuss 
Akad.  Berl.,  '82,  '83,  '85.  Neur.  Centralblat.  '97, 
p.  878. 

11.  Gad  and  Flateau,  Neurol.  Centralblat,  1896,  p.  147. 

12.  Sherrington,   Phil.   Trans.   Roy.   Soc.   Lond.,   1898, 

p.  136. 

13.  Margulies,  Wien.  klin.  Rundschau,  1899,  pi.  925. 

14.  Turner,  Stewart  P.:  J.  N.  and  M.  Dis.,  June,  1902, 

Vol.  29,  No.  6,  p.  321. 

15.  Buchanan:    Jour,   of  Physiol.,  Vol.  xx,  p.   95-190. 

Ibid.  Vol.  vxi,  p.  384,  1899. 

16.  Waller,  A.  D.:  Lancet,  1881,  Vol.  2,  p.  83.    Jour,  of 

Physiol.,  Vol.  vxi,  1890,  p.  384.    Brain,  1880,  p.  179. 

17.  Lombard:  Inter.  J.  M.  Sc.,  1887,  p.  88. 

18.  Sahli:  Treatise  on  Diagnostic  Method  of  Examina- 

tion, 1914. 

19.  Jendrassik:    Beitrage  zur  lehre  vor  den  Schneu- 

reflex,  A.  F.  K.  M.,  1883. 

20.  Lombard:    Loc.   Cit.   17.     Also,   Jour.   M.   and  N. 

Diseases,  Feb.  1890. 

21.  Bodwitch  and  Warren:  Bost.  Med.  and  Surg.  Jour., 

May  31st,  1888.  Journ.  Physiol.,  Vol.  xi,  1890, 
p.  384. 

22.  Waller:   Loc.  Cit.  No.  16. 

23.  Lombard:  Loc.  Cit.  No.  17.    Also,  Jour.  Med.  Sc., 

Jan.  1887. 

24.  Lanfanauer's  method  (Sahli). 
25*.  Schonborn's  method   (Sahli). 

26.  Phelps,  R.  M.;   N.  W.  Lancet,  St.  Paul,  Vol.  xil, 
p.  399. 

40 


27.  Phelps,  R.  M.,  Loc.  Cit.  No.  26. 

28.  Noys:  Amer.  Jour.  Psychol.,  April  1892. 

29.  Salhi:  Loc.  Cit.  No.  18. 

30.  Lombard:  Loc.  Cit.  No.  17. 
Waller:  Loc.  Cit.,  No.  16. 

Piper,  Kriel:  Arch.  f.  ges.  Physiol.  Vol.  cxix,  1907, 
p.  301.  Zeitschr.  f.  Biolog.  Vol.  L.  1908,  p. 
393-504. 

Buchanan,  Florence:  Quart.  Jour.  Exp.  Physiol., 
1908. 

Bodwitch:  Jour.  Physiol.,  Vol.  xi,  1890,  p.  25. 

31.  Lombard:  Amer.  Jour.  Physiol.  1887. 

32.  Waller:  Loc.  Cit.  No.  16. 
Erb:  Loc.  Cit.  No.  8. 
Lombard:  Loc.  Cit.  No.  31. 

33.  Waller:  Loc.  Cit.  No.  16. 

34.  Waller:  Loc.  Cit.  No.  16. 

35.  Waller:  Loc.  Cit.  No.  16. 

36.Diller:  Penn.  Med.  Jour.  1899,  Vol.  3,  p.  44. 

37.  Mitchell,  S.  W.  and  Lewis,  M.  J.,  Med.  News.  1886, 

Feb.  13.  p.  20. 

38.  Sahli:  Loc.  Cit.  No.o18. 

39.  Mitchell,  S.  W.  Loc.  Cit.  No.  37. 

40.  Lombard:  Loc.  Cit.  No.  31. 

41.  Sahli:  Loc.  Cit.  No.  18. 

42.  Westphal:    Loc.  Cit.  No.  8.     Berl.  Klin.  Wochen. 

1878. 

43.  Lombard:  Loc.  Cit.  No.  31. 

44.  Mitchell  and  Lewis:  Loc.  Cit.  No.  37. 

45.  Piper:    Loc.  Cit.  No.  30.     Also,  Arch.  f.  d.  ges. 

Physiol.  Vol.  cxix,  p.  301,  1907.    Zeit.  f.  Biolog., 
Vol.  L,  393-504,  1908. 

46.  Med.  Diagnosis,  1907. 

47.  Bodwitch:   Loc.  Cit.  No.  30.     Also,  Jour.  Physiol. 

Vol.  xi,  1890,  p.  25. 

48.  Rowntree:  Johns  Hop.  Hosp.  Bull.,  Vol  xxiii,  No. 

252,  1912. 

49.  Provost  and  Waller:  Rev.  Med.  Sciesse-Romande, 

June  15,  1881. 

50.  Provost  and  Woller:  Loc.  Cit.  No.  49. 

51.  Rowntree:  Loc.  Cit.  No.  48. 

52.  Sahli:  Loc.  Cit.  No.  18. 

53.  Morris,  R.  E.;  J.  Amer.  Med.  Assoc.,  Vol.  Ixvi,  1916, 

p.  1922. 

41 


54.  Loc.  Cit.  No.  46. 

55.  Warner:   Med.  News,  Philadel.,  1892.    Also  Jour. 

Physiol.,  Aug.  3,  1884. 

56.  Grashey:  Arch.  f.  Psych.,  1885 

Schafer  and  Horseley:  Jour.  Physiol.,  Vol.  5. 
Peterson:  N.Y.  Med.  Jour.  March  10,  1894. 
Wolfenden:  British  Med.  Jour.  May  19,  1888. 
Ewald:     Berl.  klin.  Wochen.,  1883,  No.  52. 
Cowers:  Dis.  of  Nervous  System,  1888,  p.  1001. 
Dana:  Medical  News,  Dec.  12,  1892. 

57.  Peterson:  Jour.  Nerv.  and  Ment.  Dis.,  Feb.  1899. 

58.  Horsley  and  Schafer;  Journ.  Physiol.  Vol.  5. 

59.  Neustaedter:  Med.  Record,  N.  Y.,  1909,  Vol.  xxvi, 

p.  91. 

60.  Morris,  R.  E.:    Journal  Lancet,'  1917,  xxvii,  p.  423. 


42 


•1 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  SO  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


DEC    1    1933 


DEC    2    1933 


JUN  1 4  1939 


MAR     1 1950 


-MAR — 7  1950 


1 


,'33 


250  d 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


• 


